Motion of a Bowling Ball
Objective:
The students will be able to make a distance
vs. time graph of a bowling ball
and have practice reading distance vs. time graphs of various motions.
Indiana Science Standards Addressed:
5.6.2 Demonstrate how geometric figures, number sequences, graphs, diagrams, sketches, number lines, maps, and stories can be used to represent objects, events, and processes in the real world, although such representation can never be exact in every detail.
4.5.4 Demonstrate how graphical displays of numbers may make it possible to spot patterns that are not otherwise obvious, such as comparative size and trends.
Materials
A bowling ball
5 - 10 stopwatches
a massive object to let the ball collide into and not hurt anyone
white boards (this is a 8 foot by 4 foot sheet of white paneling board that can be bought at most big hardware stores and is cut into 1 foot x 1 foot boards),
dry erase markers
paper towels to clean off the boards
Estimated Time:
Since this activity will take place in a fourth or fifth grade classroom it will take 45 minutes to an hour.
Procedure:
Step 1:
This is a Socratic/phenomenological form of
questioning to do a lab. One of the "hidden" purposes to this lab is to
get away from the standard, cookbook forms of the lab manual, and have the
students make the plan of attack with small
prompts from the teacher. I will repeat, you want to get away from the
"now
we'll do this" and move toward the "What do we need to do in order to make a
distance vs. time graph of a bowling ball as it rolls?"
In your mind, you know you want to have the students line at equally spaced
distances (for example every five feet) in the hall way. You could be
courteous
with your fellow teachers and warn them a day or two ahead of time. I
think it
is worth the extra trouble because this is an excellent opportunity to do
science outside of the classroom - which is an entire other story. You
would
like stopwatches in there little hands. You would like the students to all
start there stopwatches when you roll the bowling ball slowly. When the
ball
passes them you would like them to stop their stop watches. You would like
someone to collect the data in a column form so that you can make another trial
rolling the ball faster. You would like them to go into the classroom and
graph
the data (distance on the vertical axis and time on the horizontal axis).
You
can them ask questions such as "What do you notice about the best fit lines of
the two trials?" Hopefully you will get the faster trial is steeper and
the
slower trial is less steep.
Now is a good time to regroup and explain that if the line is horizontal it
means the object is stopped and the slope of the line (steepness) tells the
speed.
Step 2:
Hand out the white boards and dry erase
markers and a paper towel to clean them off. Explain to the students you
are going to walk across the front of the
class room and you would like them to make a sketch of a distance vs. time graph
(qualitative graph) of your motion. The following are some suggested
motions to
walk in order to have the students build from simple to more complicated.
a) walk at a constant speed
b) walk at a constant speed, stop for a time and walk at the original speed
c) walk at a constant speed, stop for a time and walk at a speed faster
than the original speed
d) walk slow and then speed up
e) walk fast and then slow down
f) walk forward at a constant speed and then back toward the origin
Step 3:
Have two students come up to the front of the class room.
Have one student make a distance vs. time graph but not show anyone except the
other student in front. He will try to walk like the sketch the first student
made and the rest of the
students will make a sketch of how the walking student walked. Compare the
original sketch made by the first student
Step 4 (Assessment):
Walk some method and have the students make a distance vs. time graph of your motion.
Rationale:
This lesson promotes students to learn how speed and motion appear on paper, and provides them with a visual aid to learn from.